unitfrmmain.pas

《Delphi百例》源码?禗elphi百例》源码

unit unitFrmMain;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, FileCtrl;

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Button2: TButton;
    DriveComboBox1: TDriveComboBox;
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

function GetDiskFreeSpaceEx(lpDirectoryName: PAnsiChar;
  var lpFreeBytesAvailableToCaller: Integer;
  var lpTotalNumberOfBytes: Integer;
  var lpTotalNumberOfFreeBytes: Integer): bool;
  stdcall;
  external kernel32
name 'GetDiskFreeSpaceExA';


procedure GetDiskSizeAvail(TheDrive: PChar;
  var TotalBytes: double;
  var TotalFree: double);
var
  AvailToCall: integer;
  TheSize: integer;
  FreeAvail: integer;
begin
  GetDiskFreeSpaceEx(TheDrive,
    AvailToCall,
    TheSize,
    FreeAvail);
{$IFOPT Q+}
{$DEFINE TURNOVERFLOWON}
{$Q-}
{$ENDIF}
  if TheSize >= 0 then
    TotalBytes := TheSize else
    if TheSize = -1 then begin
      TotalBytes := $7FFFFFFF;
      TotalBytes := TotalBytes * 2;
      TotalBytes := TotalBytes + 1;
    end else
    begin
      TotalBytes := $7FFFFFFF;
      TotalBytes := TotalBytes + abs($7FFFFFFF - TheSize);
    end;

  if AvailToCall >= 0 then
    TotalFree := AvailToCall else
    if AvailToCall = -1 then begin
      TotalFree := $7FFFFFFF;
      TotalFree := TotalFree * 2;
      TotalFree := TotalFree + 1;
    end else
    begin
      TotalFree := $7FFFFFFF;
      TotalFree := TotalFree + abs($7FFFFFFF - AvailToCall);
    end;
end;


procedure TForm1.Button2Click(Sender: TObject);
var
  TotalBytes: double;
  TotalFree: double;
begin

  GetDiskSizeAvail(pchar(DriveComboBox1.Drive + ':\'), TotalBytes, TotalFree);
  Label1.Caption := '该驱动器总共容量' + FloatToStr(TotalBytes) + '字节';
  Label2.Caption := '该驱动器剩余容量' + FloatToStr(TotalFree) + '字节';
end;
end.